The present invention relates to fiber-reinforced composites.
Conventional ceramic materials are used extensively as engineered materials and products. They are very hard materials with good thermal resistance and corrosion resistance. They tend, however, to incorporate defects during formation processes, which lead to strength faults under specified temperature and pressure conditions. These materials, while they are very hard, are also very brittle. This can result in splintering and cracking upon sudden or rapid loss in temperature, or upon impact with another material of high hardness. Fiber-reinforced ceramic composites offer significant improvements with respect to fracture resistance. They are well known and are important in the ceramic industry for high temperature engineering components, such as gas turbine and diesel engines where high temperature resistance are required. However there is a compromise in strength or load-bearing capacity.
In U.S. Pat. No. 6,251,815, issued Jun. 26, 2001 to Triplicane A. Parthasarathy and Ronald J. Kerans, we disclosed an improved fiber-reinforced ceramic composite material in which reinforcing fibers having different coefficients of thermal expansion were used in selected regions of the composite structure to reduce thermal gradient induced stresses. We have now found that the composite properties can be further enhanced by varying the matrix composition in selected regions of the composite.
To augment the load-bearing capacity, the composite has a metallic region within the matrix of the composite. This supplements the conventional ceramic materials to compensate for a deficiency in load-bearing capacity as well as thermal conductivity, which hinders use of ceramic materials for a specified purpose. Carefully selected metal components may cure one or several of these deficiencies. The resulting composite material will better withstand high temperature, and display less rigid and more ductile characteristics with less tendency to fracture when struck hard or cooled or heated rapidly. In addition, the ceramic regions are expected to be carefully varied for optimal properties.
Accordingly, it is an object of the present invention to provide a fiber-reinforced metal-ceramic composite material.
Other objects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.